"It's a good knife, son," he said, "but it's no surgical instrument. Some one lend me a razor, I use a safety myself."

Of the stock of razors that were handed to him, the big man took one, sterilized it in some boiling water from the dining car, and prepared to make an incision in the girl's leg just above the fang marks.

But no sooner had the blade touched the skin and drawn a little blood, than with a yell the father leaped straight at the inspector, flashing a knife as he did so. Not expecting an attack, the government man would have been taken unawares, but that is a land of quick action, and before the Mexican could bring his arm down, he found his wrist seized, and a revolver barrel an inch from his nose stopped his onward rush.

"That's a Greaser's gratitood, every time," said the holder of the gun. "Go ahead with your job, pard, and if this ornery cayuse so much as squirms, I'll give you an elegant opportoonity to perform a little operation for bullet extraction."

The inspector, who, seeing that the danger was averted, had gone back to his task, merely nodded. He made several wide and deep incisions, thinking that scars were better than death, and then, despite the crying of the girl and the fluent curses of the father, rubbed soda in the wounds with a vigorous hand.

"There!" he said, as he completed the task. "I think she'll do all right now!"

"But is that a sure preventive?" asked the boy.

"No, son," was the reply. "To be honest with you, nothing's sure against a rattler, because, you see, some folks' constitutions are worked on more easily than others, but in a certain number of cases the soda fixes it. That is, if you're not afraid to cut deep enough."

"Then," Roger said, "it just means that you've probably saved the girl's life?"

"Well," replied the other, "that's putting it a little strongly. And, anyhow, if you're on the Survey, you know mighty well that when government men do that sort of thing they don't talk about it."